A number of implements exist for crushing or crimping cut crops such as hay of various stock or stem thicknesses. These implements have a variety of roller arrangements, some of them being relatively flat, some of them having a toothed structure of various tooth configurations and some of them being a combination of toothed and flat surface rolls. The prior art implements also have a variety of upper deflecting plates to assist in fluffing the crimped or crushed crop and a variety of windrowing vanes to gather the crop into a more concentrated windrow.
The drive means for the known devices typically employ a combination of sprockets and flexible chains, some of them driving one roller which in turn drives the engaging mating roller while others provide a chain drive for both rollers. These drive means are normally positioned at one end of the implement so that each driven roll is driven from one end only. One prior art device drives one roll from one end and the other roll from the other end. None of the known previous crop conditioning implements drive any roll from both ends.
One roll normally has an axis which is fixed relative to the implement frame, the other roll being radially movable within defined limits, and being biased toward the fixed roll. The means for biasing the movable roll with respect to the axially stationary roll is typically a coil tension spring. Additionally, a coil tension spring is frequently used to either adjust for different chain length caused by motion of one roll with respect to the other or to maintain chain tension.
Several prior art implements have complex arrangements for maintaining timing between the crimping or crushing rollers.
Substantially all of the known prior art devices are configured as a trailer connected to the draw bar of a tractor and powered by the power takeoff of the tractor. Thus, at the end of each operational pass across a crop field, the conditioner will trail behind the tractor, with the crushing or crimping rolls normally continuing to rotate unless the power takeoff is turned off. Thus, there is a chance for uncontrolled scattering as the tractor turns at the margins of the field. There is also a chance for damage to the implement because the ground is more likely uneven at the field margins and the implement could encounter not only uneven terrain but foreign objects such as limbs, stones or stumps.
Some of the prior art devices have means to maintain the rolls substantially parallel even when the crop is particularly thick at one point between the rolls causing increased separation of them. When this occurs, the thicker portion of the crop will be appropriately crimped or crushed while the thinner crop portion between the rolls may remain untouched and thereby untreated or unconditioned.